HK1189378B - Headspace modification method for removal of vacuum pressure and apparatus therefor - Google Patents

Description

Headspace modification method for removing vacuum pressure and apparatus therefor

The present application is a divisional application of an invention patent application entitled "headspace modification method for removing vacuum pressure and apparatus therefor", having an international application date of 2009, 5, 18, international application number PCT/NZ2009/000079, national application number 200980124882. X.

Technical Field

The present invention relates generally to a method of hot filling a lightweight vessel by modifying the headspace used to remove vacuum pressure and an apparatus for use in the method. This is achieved by: filling a container with a heated fluid, which term is used in this specification to include both liquids and gases, unless otherwise specified; sealing the contents of the container from contaminants from the outside air; and adjusting the pressure of the headspace during the capping process such that the vacuum force generated within the container is eliminated after the fluid cools. The headspace modification process moves the fluid located below the headspace in the upper neck region of the container downward before allowing the fluid contents to cool and labeling the container. The present invention also relates to hot-fill and pasteurized products packaged in thermoset polyester containers and is particularly useful for packaging oxygen sensitive foods and beverages where a longer shelf life is desired.

Background

So-called 'hot-fill' containers are well known in the art, whereby manufacturers supply PET containers for various liquids that are filled into the containers and the liquid product is typically at or about 85 degrees C (185 degrees F) at elevated temperatures.

The container is made to withstand the thermal shock of the liquid being held heated, creating a 'thermoset' plastic container. This thermal shock is a result of the introduction of a hot liquid at the time of filling, or the heating of the liquid after it has been introduced into the container.

However, once the liquid cools down in the capped container, the volume of liquid in the container decreases, creating a vacuum within the container. This liquid contraction causes vacuum pressures that pull the side and end walls of the container inward. This in turn leads to their deformation if the plastic bottle walls are not constructed rigid enough to withstand such forces.

Typically, vacuum pressure has been accommodated through the use of vacuum panels, which deform inwardly under vacuum pressure. The prior art discloses a plurality of vertically oriented vacuum panels that make the container resistant to the rigors of the hot-fill process. Such vertically oriented vacuum panels are arranged substantially parallel to the longitudinal axis of the container and flex inwardly toward the longitudinal axis under vacuum pressure.

In addition to the vertically oriented vacuum panels, many prior art containers also have flexible base regions to provide additional vacuum compensation. Many prior art containers designed for hot-filling have various modifications to their end walls or base regions to allow as much inward deflection as possible to accommodate at least some of the vacuum pressure generated in the container.

However, even with such significant movement of the vacuum panel, the container requires further reinforcement to prevent distortion under the vacuum force.

The liquid shrinkage resulting from the cooling of the liquid causes the formation of a vacuum pressure. The vacuum panel flexes to a degree that reduces the vacuum force by effectively creating a smaller container to better accommodate the smaller volume of contents. However, this smaller shape is held in place by the vacuum force generated. The more difficult it is for the structure to flex inward, the greater the vacuum force that will be generated. In prior art proposals, a significant amount of vacuum may still be present in the container, and this tends to distort the overall shape unless a large, annular reinforcing ring is provided in a horizontal or transverse orientation, typically at least 1/3 away from the end for the container.

The present invention relates to hot-fill containers and may be used, by way of example, in conjunction with the hot-fill containers described in international applications published under numbers WO02/18213 and WO2004/028910 (PCT specifications), the specifications of which are also incorporated herein in their entirety where appropriate.

The above-mentioned PCT specification is background on the design of hot-fill containers and to overcome or at least alleviate problems associated with such designs.

When such transversely oriented panels are arranged in the container side wall, end wall or base region, there is a problem even after the vacuum is completely removed from the container when the liquid is cooled down and the panel is inverted (inverted). The container leaves the filling line at a slightly higher than normal ambient temperature and the panel is inverted to achieve ambient pressure within the container, as opposed to the negative pressure found in the prior art. The containers are labeled and often refrigerated at the point of sale.

This refrigeration provides further product shrinkage and in containers with very little side wall structure (in so-called 'glass-looking' bottles) there may therefore be some panel (paneling) created on the container which is unsightly. In order to overcome the production of such panels, attempts have been made to provide a base transverse panel having a greater potential for shrinkage than required, so that it may be forced to invert against the forces of the small head space present during filling. This creates a small positive pressure when filling, and this positive pressure provides some relief for the situation. When further cooling occurs, for example during refrigeration, the positive pressure may drop and may provide ambient pressure at the refrigeration temperature and thus avoid the creation of panels in the container.

However, this situation is very difficult to design successfully because it depends on utilizing a larger headspace for compression when the seat is inverted, and it is less desirable to introduce a larger headspace into the container than is required to maintain product quality.

Although it is desirable to lower the liquid level in the container to avoid spillage when opened by the consumer, it has been found that providing too much positive pressure potential within the base can cause some product spillage when the container is opened, particularly if at ambient temperature.

In most filling operations, the container is typically filled to a level slightly below the highest level of the container, which is at the top of the neck finish.

It is desirable to keep the container headspace as small as possible to provide tolerance for slight differences in product density or container capacity, to minimize spillage and waste of spillage from liquids on high speed package filling lines, and to reduce container shrinkage from cooling the contents after hot filling.

The headspace contains gases that may at any time harm certain products or impose additional requirements on the structural integrity of the container. Examples include products that are sensitive to oxygen and products that are filled and sealed at high temperatures.

Filling and sealing rigid containers at elevated temperatures can create significant vacuum forces when too much headspace gas is present.

Accordingly, in the case of containers filled at high temperatures, less headspace gas is desirable to reduce the vacuum forces acting on the container, which can compromise structural integrity, cause container stress, or significantly distort the container shape. This is also the case during pasteurization and retort processes, which involve first filling the container, sealing, and then subjecting the package to elevated temperatures for a sustained period of time.

Those skilled in the art are aware of several container manufacturing thermosets that are used to improve the heat resistance of packages. In the case of polyesters, for example polyethylene terephthalate, the heat-curing process essentially involves relieving the stresses that develop in the container during its manufacture and in order to modify the crystalline structure.

Typically, polyethylene terephthalate containers used for cold-filled carbonated beverages have higher internal stresses and smaller crystalline molecular structures than containers used for hot-fill, pasteurization, or retort production applications. However, even for containers such as those described in the above-mentioned PCT specifications (where there is little residual vacuum pressure), the neck finish of the container still needs to be very thick in order to withstand the temperature of filling.

PCT patent specification WO2005/085082 of the present applicant, which is incorporated herein by reference in its entirety where appropriate, describes a previous proposal for a headspace displacement method.

Where reference is made in this specification to any prior art, this is not an admission that it forms part of the common general knowledge in any country or region.

Disclosure of Invention

In view of the above, it is an object of one possible embodiment of the present invention to provide a headspace sealing and modification method that can be used for removal of vacuum pressure so that there is substantially no residual force within the container.

It is a further object of one possible embodiment of the present invention to provide a headspace compression method whereby air, some other gas or liquid, or a combination thereof, is charged into the headspace at a sealed pressure to create an increased pressure in order to eliminate the effect of vacuum pressure created during cooling of the product.

It is a further object of one possible embodiment of the present invention to provide a headspace modification method whereby a sterile or heated liquid, or air, or some other gas, or a combination thereof, is filled into the headspace under sterile conditions to create a positive pressure, so as to eliminate the effect of the vacuum pressure created during cooling of the product.

It is a further object of one possible embodiment of the present invention to provide a headspace modification method whereby sterile air, or some other gas or liquid, or a combination thereof, is filled into the headspace at a sealed pressure to eliminate the effect of vacuum pressure created during cooling of the product.

It is a further object of one possible embodiment of the present invention to provide a headspace modification method whereby a compression seal is applied to a neck finish of a container.

It is a further object of one possible embodiment of the present invention to provide a headspace displacement method whereby a compressive seal is applied to a neck finish, which compressive seal may be forcibly displaced into a container prior to cooling of the liquid contents, whereby a positive pressure may be introduced into the container.

Additional and alternative objects of the invention, all of which are to be read separately, in all of its embodiments at least provide the public with a useful choice.

According to one aspect of the present invention there is provided a container having a seal or cap including or adapted to provide an opening or aperture into said container for the introduction of at least one fluid under pressure, said opening or aperture also being sealable to provide a controlled increase in internal pressure within the container before the heated contents therein cool.

According to a further aspect of the present invention there is provided a container having a seal or cap applied temporarily whereby an opening or aperture into the container for the introduction of at least one fluid under pressure is provided by an incomplete seal formed between the cap and the neck finish of the container, the opening or aperture also being sealable under compression to provide a controlled increase in internal pressure within the container before the heated contents therein cool.

According to a further aspect of the present invention there is provided a container having a seal or cap which provides a temporary seal immediately after filling and having an aperture or opening which is accessible under substantially sterile conditions for the introduction of at least one heated and/or sterile fluid, the aperture or opening being further sealable under substantially sterile conditions so as to provide a controlled increase in internal pressure within the container following cooling of the heated contents within the container.

According to a further aspect of the invention, a method of filling a container with a fluid comprises: introducing a fluid through the open end of the container such that the fluid at least substantially fills the container; heating the fluid before or after the fluid is introduced into the container; providing a seal or cap having an opening or aperture; providing a method of supplying at least one fluid through an opening or orifice; and sealing the opening or aperture to compensate for a subsequent pressure reduction in the headspace of the container under the seal or cap after the heated contents cool.

According to a further aspect of the invention, a method of filling a container with a fluid comprises: introducing a fluid through the open end of the container such that the fluid at least substantially fills the container; heating the fluid before or after the fluid is introduced into the container; providing a seal or cap having an opening or aperture that is initially sealed; providing cooling of the heated contents; further provided is a method of subsequently accessing an opening or orifice and injecting at least one fluid through the opening or orifice; and sealing the aperture to compensate for a pressure decrease in the headspace of the container after the heated contents cool.

According to a further aspect of the invention there is provided a container having an upper portion with an opening into said container, said upper portion having a neck finish adapted to include a seal after introduction of a heated or heatable liquid into the container, said seal being inwardly compressible or mechanically movable before or after the liquid is heated so as to increase the pressure in the headspace.

According to a further aspect of the invention, a method of filling a container with a fluid comprises: introducing a fluid through the open end of the container such that the fluid at least substantially fills the container; heating the fluid before or after the fluid is introduced into the container; the open end is provided with a movable seal to cover and contain the fluid, said seal being adapted to compress the headspace of the container to compensate for a subsequent reduction in pressure in the headspace of the container below the seal as the heated contents cool.

According to a further aspect of the present invention there is provided a container filling apparatus for filling a container as defined in the seven paragraphs above, or for performing the filling method as defined in the paragraph above.

According to a further aspect, there is provided a seal or cap for a container, the seal or cap being configured to: for use in any of the embodiments of the container of the invention or in any of the embodiments of the method of the invention or for use in any of the embodiments of the container filling apparatus of the invention.

According to a further aspect there is provided a seal or cap for a container comprising the features of the seal or cap recited above in any of the first three aspects of the container of the invention.

Further aspects of the invention that should be considered in all its novel aspects will become apparent from the following description.

Drawings

Figures 1a-b and 2a-2b show an embodiment of a prior art container from WO2005/085082 with a mechanically compressible cap applied to seal a beverage;

figures 3a-3b illustrate the use of the compression cap of figures 1 and 2 from further prior art from WO 2005/085082;

4a-b and 5a-c illustrate a container and cap according to a possible embodiment of the invention;

FIGS. 6a-c illustrate additional embodiments of the present invention using sealed chambers;

FIGS. 7a-c, 8a-c, 9a-c, 10a-f, 11a-c, 12a-c, 13a-c, 14a-c and 15a-c illustrate further embodiments of the invention using sealed chambers;

16a-c show further possible embodiments of the invention;

17a-c show further possible embodiments of the invention;

FIG. 18 shows a further possible embodiment of the invention using a sealed chamber;

FIGS. 19a-b illustrate a possible embodiment of the present invention in the form of a capping machine;

FIGS. 20a-f show further examples of alternative embodiments of the present invention;

21a-f show a further alternative for a suitable plug mechanism in the cap;

FIGS. 22a-c and 23a-c graphically illustrate a possible method of the present invention;

figures 24 to 27 diagrammatically show a further possible embodiment of the invention in the form of a capping machine; and

figures 28a-d, 29a-d and 30a-b show further embodiments of the invention using sealed chambers.

Detailed Description

The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

As discussed above, in order to accommodate vacuum forces during cooling of the contents within a thermoset container, the container has typically been provided with a series of vacuum panels around its sidewalls and an optimized base portion. Under the influence of the vacuum force, the vacuum panel deforms inwardly and the base deforms upwardly. This prevents unwanted twisting elsewhere in the container. However, the container is still subject to internal vacuum forces. The panel and base merely provide a suitable resistance structure against this force. The greater the structural resistance, the greater the vacuum force will be present. Additionally, the end user may feel the vacuum panel while holding the container.

Typically at a bottling plant, the containers will be filled with a hot liquid and then capped before being subjected to a cold water spray which results in the formation of a vacuum within the container, which the container structure needs to be able to accommodate. The present invention relates to a hot-fill container and a method for substantially removing or substantially eliminating vacuum pressure. This allows much greater design freedom and the opportunity for light weight, since there is no longer any requirement for structures that withstand vacuum forces that would otherwise mechanically distort the container.

As can be seen in the prior art solutions in fig. 1a-b and 2a-2b, when hot liquid (21) is introduced into the container (1), the liquid occupies a volume defined by the first upper liquid level (3 a). If the compressible cap (8) is applied to the container neck (2) immediately after filling, a vacuum is created in the headspace (23 b), which headspace (23 b) is above the liquid and below the sealing surface (10) of the compressible cap, which sealing surface is the lower boundary of the compressible internal chamber (9), which compressible internal chamber (9) engages with the outer part of the cap (8). The vacuum in the headspace is typically released only when the cap is removed. The vacuum force remains substantially constant while the cap (8) is held in place. If the walls of the container are bent or flexed inwardly, the vacuum pressure level may be reduced to a small extent.

Referring to fig. 3a-b, further embodiments of the prior art invention are shown.

However, as disclosed in the prior art, mechanical compression of the movable seal to achieve positive pressure within the cap structure occurs only when the container has cooled, as shown in fig. 2 a-b. This has the obvious disadvantage of moving the non-sterile wall surface of the cap member into communication with the liquid content of the container. Such contamination cannot be tolerated and therefore one embodiment of the invention only provides for such mechanical compression of the headspace to occur immediately after the cap is applied.

In this way, the mechanical compression can achieve a positive pressure while the contents of the container are in a heated state, and subsequently enable the container to cool without panels. The cap element entering the container headspace under compression will thus be sterilized by the heated contents before cooling. It will be appreciated that a number of different configurations are contemplated for providing an initial sealing configuration which is forced downwardly to displace the liquid contents to a greater extent. A 600ml sized container, for example, would require a displacement of about 20-30cc of liquid. A container in the 2000ml size range would require a displacement of about 70cc of liquid.

It is envisaged that the cap may be metallic or plastic and in alternative embodiments may be pushed into the neck of the container rather than screwed in and may be lockable in the required position.

The cap may be controllably moved downwardly by any suitable mechanical, electrical or other means, or manually.

The method of the present invention allows for a variety of variations in mechanical compression to be explained, but for larger containers where significant downward movement is required, it is contemplated that only some of the compressive force is derived from the compressible cap, and more significantly, the remainder is derived from the method discussed in the following disclosure.

Referring to fig. 4a and 4b, an exemplary embodiment of the invention is shown having a cap (80) engaged with the container neck (2). The figures from 4a onwards all refer to the upper part of the container shown analogously in figure 4 a.

According to further aspects of the invention, and with reference to fig. 4a and b, and 5a-c, a cap may be applied to the open end (20) after introduction of the liquid (which may have been heated or adapted for later heating), the cap including a small opening or orifice (81). A headspace (23 a) is thus contained in the container below the main cap body (80) and above the fluid level (40). The headspace (23 a) is in communication with the outside air at this stage and is therefore at ambient pressure and allowed to have a fluid level (40).

As seen in fig. 6a-c, in one embodiment, a sealed chamber (84) is applied over the neck finish and cap combination to seal the fluid from the outside air (the upper, closed end of the structure 84 is not shown). As shown, the lower part of the chamber (84) may be sealed against the outer boundary (11) of the neck support ring, the horizontal boundary (12) of the neck support ring and under the neck support ring (13), after introduction of the compression force, as indicated by the arrows, e.g. by injection of air or some other gas, the increased pressure within the sealed chamber serves to subsequently increase the pressure within the headspace (23 b) and also forces the fluid level (40) to a lower point due to the subsequent expansion of the plastic container.

As an alternative to gas injection, a heated liquid, such as heated water, may be injected. This would provide an additional advantage because the injected liquid would not be subject to the expansion that typically occurs when injecting gas into a heated environment. Thus, less force is ultimately applied to the side walls of the container during the early hot-fill stage.

Further, the injected liquid will shrink less than the gas when subsequently cooled. For this reason, less liquid injection into the headspace is necessarily required to provide compensation for the anticipated vacuum forces that would otherwise occur.

Referring now to fig. 7a-c (compression force not shown), the stopper mechanism (82) is moved downwardly from the delivery device (83) toward the orifice (81) while pressure is maintained within the sealed chamber (84).

As can be seen in fig. 8a-c, the hole is permanently closed by placing a plug (82) into the hole (81) while pressure is maintained within the sealed chamber (84).

At this point, as can be seen in fig. 9a-c, the headspace (23 b) is filled at a controlled pressure depending on the amount of gas delivered, and the sealed chamber can be used for withdrawal of the delivery device (83) after the pressure in the chamber is released as the container leaves and returns to the filling line.

As shown in fig. 10a-c, as the bottle then travels along the filling line and cools, the headspace (23 b) expands due to liquid volume contraction. The fluid level (40) drops to a new position (41), and the pressurized headspace (23 b) expands and loses some or all of its pressure as it forms a new headspace (23 c).

However, it is important that once the contents cool, there is no residual vacuum in the container.

As an alternative, and as shown in fig. 10d-f, the plug 92 may be temporarily attached to the cap during production of the cap (e.g. by means 921). Liquid or gas as shown in the example can be injected under pressure in the same manner to surround the plug under pressure and into the headspace of the container and then the pusher mechanism 93 is forced downward to advance the plug 92 permanently into the hole. In this alternative, it is not necessary to load a push rod with multiple stopper mechanisms.

A further example of such an alternative is provided in fig. 18. In this embodiment of the invention, the cap 80 has a plug 92 temporarily attached by a member (not shown). Seal chamber 84 surrounds the cap and provides an internally sealed chamber headspace 87 by compression of seal ring 89 against the upper surface of the cap. Gas or liquid, or a combination of both, is injected from pressure source 888 into chamber headspace 87 through inlet 86 and into the container headspace through the void around the plug. Once the desired pressure is achieved within the container, the push rod 88 is advanced downwardly to force the plug 92 into position within the cap and thereby seal the container headspace at the desired pressure. This serves to achieve precisely the calculated internal pressure upon sealing of the container when the stopper is advanced into the final position. This serves for early compensation of the subsequent vacuum effect created by cooling of any heated contents within the container.

Referring to fig. 19a and 19b, the present invention can be made to operate in much the same manner as a typical capping station on a filling line. A typical capping machine head unit 101 encloses the sealing unit 84 and provides the function of sealing and pressurizing the container by sealing the cap of the container. A typical capping unit may optionally have twisted the cap into place but the container remains unsealed as a result of the plug being provided in an 'unplugged' position within the cap and allowing the passage of liquid or gas between the inside and outside of the container. The exact moment of sealing the container occurs when the stopper is tamped into place and the headspace within the cap is not at ambient pressure, as is typical in the filling and capping areas of the prior art capping processes, whereas according to the present invention, a headspace modification unit 102 may receive the capped container 1 and then pressurize the container immediately prior to sealing the container with the cap, the headspace modification unit 102 comprising a capping head unit 101, a pressure sealing unit 84 and a rotatable turret 103.

As an alternative, the headspace modification unit 102, which includes the capping head unit 101, the pressure sealing unit 84, and the rotatable turret 103, may also perform the usual functions of a typical capping machine. The unit may receive an empty container, apply a cap containing a stopper and then twist the cap into place, and pressurize the container prior to final sealing of the container by advancing the stopper or some other sealing method.

Further examples of alternative embodiments of the present invention are shown in fig. 20 a-f. The cap 80 may incorporate a plug 182 of rubber (or other suitable material) within the cap. This would provide the advantage of having an initial leak-proof seal with respect to the container prior to pressurizing the headspace. In this way, the container may be filled with pressure from a liquid or gas prior to cooling of the contents (e.g., immediately after filling by overpressure and capping), or the process may occur after the contents have cooled and a vacuum exists within the container. For example, the cap and sealing plug 182 may be sterilized by very hot water 66 after the liquid contents have cooled. This will sterilize the upper surface of the cap and then heated liquid can be injected to compensate for the vacuum pressure. After the injection needle 202 is withdrawn, the heating fluid being sterilized may be removed as the container is removed from the pressure chamber. Rubber seal 182 has closed and sealed the container to prevent any communication between the headspace below the cap and the outside air present when the chamber is open.

Further alternatives for suitable stopper mechanisms within the cap 80 are shown in fig. 21 a-f. A ball valve type housing 882 may be used to provide an aperture through which headspace modification may be performed within the pressure chamber unit, as previously described. Once the headspace has been pressurized, turning push rod 883 can close the ball valve while the headspace remains at the correct pressure, as shown in fig. 21 d-f.

Figures 22a-c illustrate a general exemplary method of headspace modification using the method of the present invention. An empty container (not shown below the neck finish) is filled or even 'overfilled' to the rim of the neck finish and a cap is applied, the cap having an opening through which headspace modification can be effected, for example by a ball valve closure. The capped neck finish is contained at least within a pressure chamber (not shown) and the container is placed under a calculated pressure. This pressure increase may be by injection of a gas, as in the example shown, or by over-injection of another liquid. During this process, the vessel will increase in size to the point that the fluid level is allowed to drop (if gas is being injected) and then the ball valve housing can be closed to maintain the increased pressure within the vessel.

The same process can occur using the more general "push-pull" type sports shell ('push-pull' typesports), as shown in a similar manner in fig. 23 a-c.

As a further alternative to the present invention, with reference to figures 17a-c, in order to remove the need for a hole or plug mechanism within the cap itself, a normal cap may be applied by the capping unit but not forced to be twisted into place. The neck finish can then be enclosed within the chamber 84 and fluid or gas forced into the container through the gap between the cap and the thread mechanism of the neck finish, as shown by the passage of liquid 86. Once the desired pressure is achieved, the cap is twisted into place by advancing the twist ram 85 within the chamber 84 as shown in figure 17b while maintaining the container headspace under pressure. In this embodiment, the method may be implemented using standard caps rather than modified caps. Fig. 17c shows the cap 80 correctly twisted with the twist ram 85 removed immediately prior to the container head being removed from the chamber 84.

It will be appreciated that the present invention provides a number of options for implementing headspace modification processes by modifying typical capping machines. Such a mechanism can also be readily used to provide a container capping function in addition to modifying the headspace during the process.

Fig. 24 shows how the container may be contained within a typical seal chamber 84 from immediately below the neck support ring 33 of the container.

Fig. 25 shows how the entire container may be contained within the sealed chamber 84. In this embodiment, the container is not forced by the increased pressure until after exiting the sealed chamber.

Fig. 26 shows an alternative embodiment of the present invention. It is contemplated that seal chamber 84 may optionally include a lower seal skirt 884. In this example, a seal of soft material may be inflated under water or gas pressure through inlet 883 to make intimate contact with the container shoulder. Gas or liquid may then be filled into the pressure chamber headspace 87 through inlet 86 to retrofit the container headspace prior to final sealing.

Fig. 27 shows how the sealing chamber of fig. 26 may be incorporated into a typical capping unit station 844 with a rotating head applicator. This will allow the modified capping unit to apply the cap in the normal manner, but modify the headspace before applying the twist that seals the cap on the container.

To facilitate the present invention, complete or substantial removal of the vacuum pressure by moving the headspace prior to liquid contraction now results in the ability to remove a significant amount of weight from the sidewall due to the removal of the mechanical distorting forces.

According to a further aspect of the invention, and with reference to fig. 11a-c, a cap may be applied after the liquid has been introduced (which may have been heated or adapted for later heating), the cap comprising a small opening or aperture (81), the opening or aperture (81) being temporarily covered by a communication seal (91). A headspace (23 d) is thus contained in the container below the main cap body (80) and above the fluid level (40). The headspace (23 d) is not in communication with the outside air at this stage and is therefore at the usual vessel pressure during the cooling stage on the filling line.

As seen in fig. 12a-c, once the container has cooled, typically to a level for labeling and dispensing, the headspace (23 e) will be in an expanded state by virtue of the reduced fluid level, and a vacuum will have been created due to the contraction of the heated liquid within the container.

As seen in this preferred embodiment of the invention, to remove the vacuum pressure, a sealing chamber (84) is applied over the neck finish and cap combination to seal the communication seal (91) from the outside atmosphere (the upper, closed end of the structure 84 is not shown).

After introducing the sterilising medium (66) for the sterilisation of the inner surfaces of the sealed chamber (84) and the communication seal (91), for example by injecting heated water, preferably above 95 degrees C, or a mixture of heated water and steam.

Referring now to fig. 13a-c, the plug mechanism (82) is placed down towards the orifice (81) from the delivery device (83) while the sterilising medium is retained within the sealed chamber (84). The stopper mechanism pierces the communication seal (91) and is temporarily withdrawn again as shown in figures 14a-c, providing communication between the sterile volume in the sealed chamber above the cap (80) and the headspace (23 e) below the cap.

As can be seen in fig. 14a-c, the sterilising medium (e.g. heated water at 95 ℃) is pierced by the communication seal, immediately sucked into the container through the opening (81). This causes an equalisation of the pressure within the vessel or removal of the vacuum pressure, so that the level of the headspace (23 f) rises higher. In another preferred embodiment, the liquid is in fact injected into the container at a small pressure supplied from the sealed chamber (84), so that the pressure inside the container is in fact a positive pressure and the head space is in fact very small.

The integrity of the product volume within the container is not compromised because the environment above the cap has been sterilised before communicating with the headspace, and prior to the described headspace replacement method, the additional liquid supplied into the container replaces the 'lost' volume within the container due to shrinkage of the heated liquid.

After the pressure has been equalized, with reference to fig. 15a-c, the delivery device (83) is advanced again so that the plug (82) will be inserted into the hole to permanently close it.

At this point, the headspace (23 f) is under a controlled pressure, as described above, depending on the volume of liquid that has been delivered to compensate for previous liquid shrinkage.

After the sterilising medium and/or pressure within the chamber is released, the sealed chamber can now be used for withdrawal of the delivery device (83) as the container leaves and returns to the filling line, which withdrawal can now take place.

A method of compensating for the vacuum pressure in a container is thus described. Referring to fig. 16a-c, the original headspace level (40) undergoing subsequent cooling of the heated contents within the closed container provides for the presence of a vacuum in the first headspace (23 d). After compensation according to this embodiment of the invention, the headspace level varies and perhaps rises (41) depending on the pressure contained within the headspace, and the pressure within headspace 23f is now in fact preferably at ambient pressure or preferably slightly positive pressure, so that the side walls of the container are supported by slight internal pressure.

Referring to fig. 28a-d, an alternative embodiment of the invention also includes a compressible cap, where compression occurs after filling and before cooling of the contents. In this way, the chamber (9) can be sterilised by the contents once it has advanced into the container, by compression which occurs when the liquid is hot. The compressible cap may be contained within the compression chamber as previously described, particularly for large size containers. A 600ml size container, for example, would require a displacement of about 20-30cc of liquid, while a 2000ml size range container would require a displacement of about 70cc of liquid. Such a large movement is difficult to achieve without access to the extremely large movable chamber of the container. Thus, to keep the chamber size to a minimum, it is contemplated that the compression chamber may provide a certain amount of gas or liquid injection, and the compressible cap may provide the remainder of the compression required. In this way, a minimum of gas is also injected into the container. Of course, it will be appreciated that for small container sizes, only a compressible cap may be utilized.

Unlike what is described in the prior art, the present invention provides that the hot liquid inside the container sterilises the underside of the internally disposed surface of the internal chamber (9) as it has been compressed into the hot liquid content.

Typically, as the product cools, a vacuum will form in the initial headspace (23 b) within the container below the cap. Such a vacuum may distort the container (1) to a certain extent if the walls are not rigid enough to withstand the forces.

However, since the internal pressure has been adjusted upwards before the product is cooled, the practical result may be a temporarily elevated pressure level during the cooling of the product, while there is essentially no pressure once the cooling of the product has ended, or perhaps even advantageously a small amount of positive pressure.

Referring to fig. 29a-d, another similar embodiment of the present invention provides a mechanical cap having mechanically controllable "out" and "in" positions. The compressible cap (8) is applied to the container (1) immediately after filling with the hot beverage. In this particular embodiment, the sealing surface (10) of the compressible internal chamber (9) moves higher than in the previous example shown in fig. 28 a-d.

Referring to fig. 30a-b, further embodiments of the present invention are disclosed. The cap structure may be a 2-piece construction or a one-piece unit whereby the compressible internal chamber (9) engages with the internal threads of the neck finish (99) and causes compression of the headspace as the cap is applied and secured to the container (1). Also, for larger size containers, this provides the ability to keep gas or liquid injection to a minimum while taking advantage of the movement of the hot liquid contents to provide an increase in container pressure when the container is sealed.

Where in the foregoing description reference has been made to specific elements or integers of the invention having known equivalents then such equivalents are herein incorporated as if individually set forth.

Although the invention has been described by way of example and with reference to possible embodiments thereof, it is to be understood that modifications or improvements may be made thereto without departing from the scope of the invention as defined in the appended claims.

Claims (45)

1. A headspace modification apparatus for receiving a filled container (1) having an open end (20, 81, 86) and a first internal pressure and for applying a cap or seal (80, 82, 91, 92) to the open end (20, 81, 86) of the filled container (1) when pressurizing a headspace of the container, the headspace modification apparatus comprising:

a sealed chamber (84, 884); and

a conveying device (83, 85, 88, 93), wherein the conveying device controls and applies a cap or seal to the container (1), and a sealing chamber (84, 884) surrounds the conveying device (83, 85, 88, 93);

wherein the sealed chamber (84, 884) is movable relative to the container (1) to engage and seal with a surface on the container (1) or on a cap (80) provided to the container (1) to connect the interior of the sealed chamber (84, 884) with the interior of the container (1) so that gas and/or liquid can be injected into the headspace through the sealed chamber (84, 884);

wherein the headspace modification apparatus further comprises a pressurization device coupled to the sealed chamber (84, 884) to increase the pressure within the sealed chamber (84, 884) and within the container (1) with a volume of gas, vapor, liquid, or a combination thereof; and

the headspace modification apparatus moves the sealed chamber (84, 884) to seal the container (1) within the sealed chamber (84, 884) when the sealed chamber (84, 884) is subjected to an elevated internal pressure to create an increased pressure within the sealed container (1), the increased pressure being higher than the first internal pressure.

2. A headspace modification device according to claim 1, wherein the headspace modification device is a capping device and the cap or seal is a cap (80) or enclosure.

3. The headspace modification apparatus according to claim 1, wherein the container is filled with a heated liquid.

4. A headspace modification apparatus according to claim 1, wherein the headspace modification apparatus is a rotary device driven by a rotatable drive turret (103).

5. A headspace modification apparatus according to claim 4, wherein the container is moved about a substantially circular path by the rotatable drive turret (103).

6. A headspace modification apparatus as set forth in claim 1, wherein said sealing chamber (84) provides a temporary seal to said container near a neck of said container.

7. A headspace modification apparatus as claimed in claim 6, wherein the sealing chamber (84) provides a temporary seal to the container adjacent a neck support ring of the neck finish.

8. A headspace modification apparatus as claimed in claim 1, wherein the delivery device (85) is a retaining apparatus for retaining the cap in position to engage the neck of a container.

9. A headspace modification apparatus according to claim 1, wherein the conveying device (85) provides a capping torque for closing the container.

10. A headspace modification apparatus according to claim 1, wherein the pressurising means provides at least one liquid and/or gas or a combination thereof.

11. A headspace modification apparatus according to claim 10, wherein at least one of said liquids and/or gases is substantially sterile.

12. A headspace modification device according to claim 1, wherein the filled container (1) has a cap (80) which is substantially in place prior to introduction into the headspace modification device.

13. A headspace modification apparatus according to claim 12, wherein the cap (80) is adapted to provide a temporary opening (81) or aperture into the container, said opening or aperture being provided for pressurisation of the headspace of the container.

14. A headspace modification apparatus according to claim 13, wherein the temporary opening (81) is covered by a seal (91).

15. A headspace modification apparatus according to claim 14, further comprising an application device for providing a sterilising medium (66) to substantially sterilise the cap (80) and/or the temporary seal (91) prior to pressurising the container through the temporary opening (81).

16. Headspace modification apparatus according to claim 12, comprising means for creating a temporary opening (81) or orifice in the cap (80), said opening or orifice being provided for pressurising the headspace of the container.

17. A headspace modification apparatus as claimed in claim 12, wherein the pressure of the headspace of the vessel is increased or increased above the headspace pressure when introduced into said headspace modification apparatus receiving the filled vessel.

18. A headspace modification apparatus as claimed in claim 12, for hot filling, wherein after hot filling, the greater pressure compensates for the pressure drop caused by cooling of the contents of the container.

19. A headspace modification apparatus according to claim 1, wherein the cap (80) is adapted to provide a temporary opening (81) or orifice and the delivery device seals or plugs the temporary opening or orifice after pressurising the interior of the container.

20. A headspace modification apparatus according to claim 19, wherein the seal or cap is adapted to be pierced so as to provide said opening or aperture and expose the headspace of the container to pressure.

21. A headspace modification apparatus according to claim 10, wherein the pressurising means provides steam.

22. A headspace modification method for applying a cap or seal (80, 82, 91, 92) to an open end (20, 81, 86) of a filled container (1) having a first internal pressure, the method comprising:

positioning a delivery device (83, 85, 88, 93) and a sealed chamber (84) containing a cap or seal over the open end (20, 81, 86) of the filled container, thereby connecting the interior of the sealed chamber (84) and the interior of the container (1),

pressurizing the interior of the sealed chamber (84) and the interior of the container (1) with a volume of gas, vapor, liquid, or a combination thereof,

moving a delivery device (83, 85, 88, 93) within the sealed chamber (84) relative to the open end (20) of the container (1) to place a cap or seal to close the open end and seal the gas, vapor, liquid, or combination thereof within the container while maintaining a second internal pressure within the container, wherein the second internal pressure is higher than the first internal pressure,

releasing the closed container (1) from the sealed chamber (84).

23. The method according to claim 22, wherein the cap or seal is a cap (80) provided for the open end (20) of the container (1) engaged with a bottle neck (2, 99).

24. A method according to claim 22, wherein a positive pressure is maintained in the container (1) before the container is released from the sealed chamber (84).

25. The method of claim 24, wherein the positive pressure does not increase within the container after the container is released from the sealed chamber (84).

26. The method according to claim 22, wherein the pressure within the sealed chamber (84) is released before the closed container (1) is released from the sealed chamber (84).

27. The method of claim 22, wherein the step of moving the conveyor (85) includes moving the cap or seal (80) vertically to engage the open end of the container.

28. The method of claim 23, wherein the step of moving the delivery device includes rotating a cap (80) onto a neck of the container.

29. The method of claim 22, further comprising the initial steps of filling and sealing the container, moving the container toward the sealed chamber, and forming or providing an opening (81) through the seal or cap (80) into the container interior.

30. The method of claim 29, wherein the seal chamber (84) is sealed against a seal or cap (80) prior to pressurizing the seal chamber (84).

31. The method of claim 29, wherein an opening (81) is formed in the seal or cap (80) when the seal or cap is positioned within the seal cavity (84).

32. A method according to claim 29, wherein the container is positioned within a sterilizing device to sterilize the cap (80) and/or the temporary seal (91).

33. The method of claim 32, wherein the sterilizing device is disposed within a sealed chamber (84).

34. The method according to claim 22, wherein the container (1) is filled with a heated fluid.

35. The method of claim 34, further comprising heating the fluid before or after introducing the fluid into the container (1).

36. A method according to claim 22, further comprising an initial step of filling and sealing or capping the container, wherein the seal or cap (80) is provided with an opening (81, 86) into the interior of the container.

37. The method of claim 36, wherein the sealed chamber (84) is sealed against a seal or cap (80) prior to pressurizing the sealed chamber (84).

38. The method of claim 36, wherein the sealing chamber (84) is sealed against the neck of the container prior to pressurizing the sealing chamber (84).

39. The method of claim 36, wherein the sealing chamber (84) is sealed against the container prior to pressurizing the sealing chamber (84).

40. A method according to claim 36, wherein the conveying means (85) controls the seal or cap (80) after moving the container into the sealing chamber (84).

41. A method according to claim 40, wherein the step of moving the conveyor (85) comprises moving a seal or cap (80) vertically so as to engage the open end of the container.

42. The method according to claim 41, wherein the step of moving the conveyor (85) comprises rotating a cap (80) onto a neck of the container.

43. The method of claim 22, wherein the volume of gas, vapor, liquid, or combination thereof comprises a heated liquid or vapor.

44. The method of claim 22, providing compensation for a pressure drop in the headspace of the container after the heated contents cool.

45. The method of claim 36, wherein after initially filling and sealing the container, the liquid contents of the container are allowed to cool prior to the step of forming the opening into the container.